Thread tension device



p 1964 M. R. LAIDIG 3,150,846

THREAD TENSION DEVICE Filed March 7, 1963 INVENTOR. WITNESS Manfred R. Lard/g TORNEY United States Patent 3,150,346 THREAD TENSION DEVICE Manfred R. Laidig, Union, N.J., assignor to The Singer Company, a corporation of New Jersey Filed Mar. 7, 1963, Ser. No. 263,521 Claims. Cl. 242-150) This invention relates to sewing machines and more particularly to an improved thread tension device designed for mounting on the bracket arm head of a family type sewing machine and an important object of the invention is to provide a generally improved device of this character.

Another object of the invention is to provide an improved thread tension device which is shorter or more compact than thread tension devices of substantially the same general type.

A further object of the invention is to provide an improved thread tension device having a clamping member especially designed to secure a part of the thread tension device to the arbor thereof.

A still further object of the invention is to provide an improved thread tension device having a tubular member which is provided with apertures designed to accommodate axially extending portions of other members of the thread tension device.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the accompanying drawings:

PEG. 1 is an elevational side view of a portion of a sewing machine bracket arm head fitted with a tension device embodying the present invention.

FIG. 2 is an enlarged scale sectional View taken on the line 2-2 of FIG. 1, and

FIG. 3 is an exploded perspective view of the tension device shown in FIGS. 1 and 2.

In the preferred embodiment of the invention illustrated in the drawings, the numeral it: indicates an overhanging bracket arm of a family type sewing machine, and the arm 16 terminates in a head 17 which supports the usual reciprocating needle bar 18, thread take-up l9, and presser bar 21. A tension release lever 22, of the type similar to that shown in United States Patent No. 2,518,703, and having arms 23 and 24, is pivotally supported in the head 17 by a screw 26. The arm 23 is operated by a presser bar lifter (not shown) whenever the lifter approaches the fully raised position. The arm 24 is biased counterclockwise by a beehive spring 27 for a purpose presently to be discussed. The head 17 also supports a thread tension device, which is generally designated by the numeral 32, and in order to support the tension device 32 the front wall 33 of the head 17 is provided with a shoulder hub 34 and an aperture 36, the inner end of which is in communication with a hole 37.

The thread tension device 32, which forms the subject of the present invention, comprises a mandrel or arbor 41 having a reduced diameter end 42 and a central bore 4-3. Adjacent to the end 42 the arbor 41 is formed with a plurality of gear teeth type slots 44 which are designed to receive an end 46 of a check spring 47 presently to be more fully described. The end of the arbor 41 remote from the end 42 is threaded, as at 48, and formed with a longitudinally extending diametrical slot 49, and the arbor 41 between the threads 48 and the slots 44 is provided with a circumferentially extending annular groove 51 designed to accommodate a spring C-clamp 52. The

check spring 47, the main portion of which is formed as a closely wound helical spring, has an arm 53, a spanner 54, a second arm 56, and a loop $7. The tension device 32 has a tension release pin 58 having a head 59, the main portion of the pin 58 being carried in the bore 43 of the arbor 41. The front end of that portion of the arbor ll which forms the gear teeth slots 44 is engaged by one side of the inner of three identical butting tension discs at, 67 and 6%.

The outer face of the disc 68 is engaged by the inner face of a guard plate 69 which carries a rearwardly extending arm 71 enterin a hole 72 formed in a plate 73 which carries thread eyelets '74 and 76, the plate 73 being carried on the hub 34. A movable adjusting plate 77, which is adjustably held in place by a screw 78, passing through a slotted hole 79 is also carried on the hub The front face of the guard plate 69 has three forwardly extending protuberances 81 which are engaged by the rear face of a first tubular member 82, which rear face has a forwardly converging frusto-conical depression 83 concentrically positioned with respect to the arbor 41. The protuberances 81 and the depression 83 provide, between the front face of the plate 69 and the rear face of the member 82, sutiicient space for the previously mentioned C-clamp 52 and an anchor disc 84 and its radially extending arm The anchor disc 84, is prevented from turning on the arbor 41 by reason of having a pair of diametrically extending lugs 37 entering the slot and the arm 86 has a forwardly extending finger which is parallel to the axis of the arbor 41 and which is received in a radial slot 39 formed in the tubular member 32. The tubular member 82. is prevented from turning on the arbor 41 by reason of having a diameter bar 91 received in the slot 49. The cup shaped portion of the member 32 receives or houses the large coiled portion of a beehive compression spring 92., and the end of the large coiled portion of the spring 92 is fastened to the tubular member 82 because the end of the large coiled portion of the spring 92 entering an aperture provided in the tubular member 82. The small coiled portion of the spring 92. engages a plastic washer 93 carried in the bottom of a cylindrical cavity 94 formed in a second tubular member 95 which has an internally threaded stem 95 designed to be screwed on the threads 48 of the arbor 41. The external surface of the tubular member 95 is roughened or knurled and fits into a cavity 97 formed in a graduated thumb handle 9%, the handle 98 being secured to the tubular member 95 by a set screw 99 which selectively engages the knurled surface of the member 95. An internal circumference 161 of the handle 98 carries an inwardly extending radial lug ltli. which under certain conditions engages the forwardly extending finger 88 of the anchor disc 84. From the above it can be seen that the second tubular member 95 houses the small coiled portion of the beehive spring 92 and that the cavity 97 of the handle 93 houses the second tubular member 95.

The tension device 3?. is assembled in the following manner. The three tension discs 66, 67 and 68 and the guard plate 69 are placed on the slotted (49) end of the arbor 41 in the order shown in FIG. 2. The portion of the check spring 47, which carries the end 46, is placed over the gear teeth type slots 4-4. The loop 57 is placed around the threaded end 43. The tension release pin 53 is placed into the bore 43 from the slotted end 49 making sure that the headed end 59 is entered last. The anchor disc is placed on the arbor 41 making sure that the finger 88 extends away from the plate 69. The spring C-clamp 52 is pushed into the annular groove 51, thereby, locking the anchor disc 84 in place. The tubular member 82 is placed on the arbor 41 with the diameter bar 91 entering the slot 49 and with the slot 89 receiving $9 the arm 86 and the finger The beehive spring 92 is placed on the arbor 41. The plastic Washer 3 is placed into the tubular member 95, which in turn is placed in thethumb handle 98, and the set screw $9 is tightened to secure the handle '98 to the member 9". After this is done the threaded stem is screwed on the threads 43 of the arbor 4-1. When the thread tension device 32 is adjusted for the greatest tension, further turning of the handle 98 will be stopped by the lug 1692 engaging the finger 83. Proper tension can be applied to the thread "(not shown) by loosening or tightening the handle 98.

Having thus set forth the nature of the invention, what I claim herein is:

1. A thread tension device for sewing machines con prising an arbor formed with a circumferentially extending annular groove, a plurality of thread tension discs carried by said arbor, a guard plate carried by said arbor and engaging at least one of said tension discs, an anchor disc carried by said arbor on the side of said guard plate remote from said tension discs, at C-cramp positioned on the side of said anchor disc remote from said guard plate and entering the annular groove on said arbor, said C- clarnp securing said anchor disc to said arbor, a compression spring carried by said arbor, means to compress said compression spring to thereby cause said guard plate to press against one of said tension discs, and a lug carried by said last named means, said lug engaging a portion of said anchor disc and thereby limiting the movement of said last named means.

2. A thread tension device for sewing machines comprising a slotted arbor formed with a circuinfercntially extending annular groove, a plurality of thread tension discs carried by said arbor, a guard plate carried by said arbor and engaging at least one of said tension discs, an anchor disc carried by said arbor on the side of said guard plate remote from said tension discs and said anchor disc having at least one lug entering the slot of said arbor, a

C-clamp positioned on the side of said anchor disc remote from said guard plate and entering the annular groove on said arbor, said C-clarnp securing said anchor disc to said arbor, a compression spring carried by said arbor, means to compress said compression spring to thereby cause said guard plate to press against one of said tension discs, and 2. lug carried by said last named means, said lug engaging a portion or said anchor disc and thereby limiting the movement of said last named means.

3. A tension device for sewing machines comprising a slotted arbor formed with a circumferentially extending annular groove, a plurality of thread tension discs carried by said arbor, a guard plate carried by said arbor and engaging at least one of said tension discs, an anchor disc carried by said arbor on the side of said guard plate remote from said tension discs, at least one lug carried by said anchor disc and entering the slot of said arbor, an arm extending radially from said anchor disc, a finger carried by the free end of said arm and extending axially of said arbor, a G-clamp positioned on the side of said anchor disc remote from said guard plate and entering the annular groove on said arbor and said G-clamp securing said anchor disc to said arbor, a tubular member carried by said arbor at the side of said C-clamp remote from said anchor disc and said tubular member having a radially extending slot positioned to accommodate the arm and finger of said anchor disc, a compression spring carried by said arbor and engaging said tubular member, means to compress said compression spring to thereby cause said guard plate to press against one of said tension discs, and a lug carried by said last named means, said lug engaging said finger to thereby limit the movement of said last named means.

4. A tension device for sewing nrachines comprising a longitudinally extending diametrically slotted arbor formed with a circumferentially extending annular groove, a plurality of thread tension discs carried by said arbor, a guard plate carried by said arbor and engaging at least one of said tension discs, an anchor disc carried by said arbor on the side of the guard plate remote from said tension discs and said anchor disc having at least one lug carried by said anchor disc and entering the slot of said arbor, an arm extending radially from said anchor disc, a finger carried by the free end of said arm and extending axially of said arbor, a G-clamp positioned on the site or" said anchor disc remote from said guard plate and entering the annular groove on said arbor and said C-clamp securing said anchor disc to said arbor, an apertured tubular member carried by said arbor at the side of said C-clamp remote from said anchor disc and said tubular member having a radially extending slot positioned to accommodate the arm and finger of said anchor disc, a beehive compression spring having a large coiled portion and a small coiled portion, the end of the large coiled portion of the beehive spring entering an aperture in said tubular member, a handle turnably carried on said arbor and designed to compress said compression spring to thereby cause said guard plate to press against one of said tension discs, and a lug carried by said handle, said lug engaging said finger to thereby limit the movement of said handle. 7

5. A tension device for sewing machines comprising an arbor; a plurality of thread tension discs carried by said arbor; a guard plate carried by said arbor and engaging at least one of said tension discs; an anchor disc carried by said arbor on the side of said guard plate remote from said tension discs; means for securing said anchor disc to said arbor; a first tubular member carried by said arbor and located on the side or" said anchor disc remote from said guard plate; a beehive compression spring having a large coiled portion and a small coiled portion, t e large coiled portion of the beehive spring being housed by said first tubular member; a second tubular member threaded to said arbor, and said second tubular member housing the small coiled portion of said beehive compression spr ng; a knurled external surface formed on said second tubular member; a hollow thumb handle housing said second tubular member; a set screw carried by said thumb handle and adapted selectively to engage various portions of the knurled external surface of said second tubular member, and a lug carried by said thumb handle, said lug engaging a portion of said anchor disc and thereby limiting the movement of said thumb handle.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A THREAD TENSION DEVICE FOR SEWING MACHINES COMPRISING AN ARBOR FORMED WITH A CIRCUMFERENTIALLY EXTENDING ANNULAR GROOVE, A PLURALITY OF THREAD TENSION DISCS CARRIED BY SAID ARBOR, A GUARD PLATE CARRIED BY SAID ARBOR AND ENGAGING AT LEAST ONE OF SAID TENSION DISCS, AN ANCHOR DISC CARRIED BY SAID ARBOR ON THE SIDE OF SAID GUARD PLATE REMOTE FROM SAID TENSION DISCS, A C-CLAMP POSITIONED ON THE SIDE OF SAID ANCHOR DISC REMOTE FROM SAID GUARD PLATE AND ENTERING THE ANNULAR GROOVE ON SAID ARBOR, SAID CCLAMP SECURING SAID ANCHOR DISC TO SAID ARBOR, A COMPRESSION SPRING CARRIED BY SAID ARBOR, MEANS TO COMPRESS SAID COMPRESSION SPRING TO THEREBY CAUSE SAID GUARD PLATE TO PRESS AGAINST ONE OF SAID TENSION DISCS, AND A LUG CARRIED BY SAID LAST NAMED MEANS, SAID LUG ENGAGING A PORTION OF SAID ANCHOR DISC AND THEREBY LIMITING THE MOVEMENT OF SAID LAST NAMED MEANS. 